This invention relates to coating compositions, more particularly to such coating compositions containing principally polybutadienes which can be cured to increased thickness at room temperature.
Generally, coatings are desirably such which can produce a desired thickness of film with less frequency of coating application. On the other hand, they should preferably be liquids of low viscosity to facilitate the coating operation.
Both of these features or requirements cannot be achieved by any known solvent-containing coating for the simple reason that the use of increased portions of solvents to lower the viscosity of the coating would result in failure to obtain sufficiently great film thickness and for another contradicting reason that the use of less solvents with a view to increasing the concentration of the coating might contribute to the thickness of coated film but would unduly increase the viscosity and hence would run counter to the ease of coating operation.
There are also known certain non-solvent type coatings comprising unsaturated polyesters and copolymerizable monomers such as styrene, which coatings could meet with the aforesaid requirements to some extent, but have a drawback in that the curing of the surface of coated film is interfered with by oxygen in the atmosphere, resulting in sticky surface finish. Another difficulty of the conventional non-solvent coatings is that their film has rather poor resistance to water and acids.